20291722395521 has 2 divisors, whose sum is σ = 20291722395522. Its totient is φ = 20291722395520.

The previous prime is 20291722395493. The next prime is 20291722395523. The reversal of 20291722395521 is 12559322719202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14839329274225 + 5452393121296 = 3852185^2 + 2335036^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20291722395521 is a prime.

It is a super-2 number, since 2×20291722395521² (a number of 27 digits) contains 22 as substring.

Together with 20291722395523, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20291722395521.

It is not a weakly prime, because it can be changed into another prime (20291722395523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10145861197760 + 10145861197761.

It is an arithmetic number, because the mean of its divisors is an integer number (10145861197761).

Almost surely, 2^{20291722395521} is an apocalyptic number.

It is an amenable number.

20291722395521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20291722395521 is an equidigital number, since it uses as much as digits as its factorization.

20291722395521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1360800, while the sum is 50.

The spelling of 20291722395521 in words is "twenty trillion, two hundred ninety-one billion, seven hundred twenty-two million, three hundred ninety-five thousand, five hundred twenty-one".